1. Field of the Invention
The present invention is related generally to movable joint assemblies and more particularly to movable joint assemblies which include a housing, a ball stud and a dust boot sealed against the housing and ball stud.
2. Related Art
Dust boots made of rubber or other similar materials are often employed to seal a movable joint assembly by preventing contaminants from entering the movable joint assembly and by capturing a lubricant, such as grease, within the movable joint assembly. Such movable joints typically include a housing and a stud which are pivotable relative to one another through a wide range of motion. The dust boot must maintain fluid tight seals with both the housing and the ball stud through the entire range of motion. Often, metal or plastic rings are placed around the circumference of the dust boot for biasing the dust boot against the housing to establish the fluid tight seals. However, the installation of the metal or plastic rings may be cumbersome and, on occasion, the dust boot may become unintentionally torn, which leads to unnecessary waste and labor to replace the torn part. The use of external rings may also require the outer surface of the housing to be machined so as to provide a surface configuration that is sufficient to produce an acceptable seal between the housing and the dust boot. The machining process further increases the cost of the movable joint.
Another option for sealing the dust boot against the housing is to capture an end of the dust boot under a crimped or spun edge of the housing. Under this option, a metal or plastic ring may additionally be placed within the dust boot to restrict unintentional pull out of the dust boot from the crimped or spun edge during full articulation of the stud and housing relative to one another. However, this option may also have certain limitations. For example, the crimping or spinning process may fail to produce an adequate seal between the dust boot and the housing. Additionally, due to the mechanical properties of common dust boot materials, the dust boot may take a so-called “compression set” after a predetermined duration of time and pressure, thereby weakening the seal between the dust boot and the housing. Overspinning or over crimping the housing onto the dust boot may not compensate for this compression set condition and may force some of the material of the dust boot to vacate the area between the mating surfaces, which presents other problems.